risk based approach to assessing acute human health risks ... · objective of assessing public...

Speaker: Cindy Ott Senior Scientist

Risk Based Approach to Assessing Acute Human Health Risks During and After a Spill

March 26, 2013

Outline

• WHY? • Objective of Assessing Public Health Risk • What is Risk Based Approach and Components

of an Acute HHRA • Challenges of Acute HHRA • Lessons Learned • Components of a World Class Acute HHRA

WHY? • Public perception that health risk occurs during

spill events – The Public smell the odours – Some people don’t feel well – Experience short term effects

• The Public still has concern despite the reassurances of the responsible party

WHY? “Residents in the neighborhood – located near the tank farm – reported that the smell contributed to nausea and headaches, and they were concerned about long-term health implications” “Documents obtained through the Michigan Department of Community Health reveal that 145 people were treated by health care providers after the July 25, 2010 spill that polluted local wetlands and the Kalamazoo River, and 320 locals reported experiencing illnesses in surveys. A total of 41 calls were also made to poison control, the most common symptoms being headaches, nausea, vomiting and respiratory problems.”

WHY? • Usually the ambient air data gathered during a

spill event be used in a risk assessment

– Detection limits of instruments higher than acute criteria

– No rigorous plan or planning for public monitoring – most occupational monitoring

– Always reactive not proactive planning – Even if no short term or long term health risks it is

hard to

Objective of Assessing Public Health Risk

• The predominant exposure pathway for public receptors during a spill event is the inhalation pathway.

• This is due to the volatilization of chemical components

within the product, after a spill, become airborne and can be carried towards areas inhabited by human receptors.

Objective: Evaluate the potential for adverse health

effects to human receptors from exposure of chemicals in ambient air during a spill event

Objective of Assessing Public Health Risk

Spill Event

Air Monitoring

Acute Risk Assessment

Shelter or Evacuate

What is a Risk Based Approach

An evaluation of the potential for adverse health effects to human receptors

resulting from exposure to chemicals

1. Problem Formulation

Four Steps of Risk Assessment

2. Exposure Assessment

3. Toxicity Assessment

4. Risk Characterization

Risk Based Approach – Acute HHRA

• Where is the spill event • Where are the chemicals –> in the

ambient air • What type of chemicals are being

released • Who lives in the spill impacted area • How are the Public exposed to

contamination -> inhalation • How long is the Public exposed

Step 1. Problem Formulation

Risk Based Approach – Acute HHRA

Components of Problem Formulation

Context: • Exposure that may occur during a Petroleum Spill

Event not during a long clean up period

• Urban or Remote Environments

• Wind Direction and Weather

Wind Direction Wind Direction


Receptors: • Humans – who is in area of impact

• All ages - birth to elderly • Sensitive populations – sick, elderly • Daycares, care homes, hospitals, schools,

residential area, parks, industrial areas, etc


Chemicals: Related to Petroleum Products • General Physical Properties

• Product vapors generally sink towards ground • Product constituent floats and/or sinks in water

• Chemical Properties • Toxicology • Where is this information found

• MSDS Sheets • Specific chemical Analysis

Components of Problem Formulation Chemicals of Potential Concern

Product Type: Crude Oil and Gasoline Product Type: Added to List for Only Gasoline

• Benzene • Isopropylbenzene • 1,2-dibromoethane

• Toluene • N-decane • 1,2-dichloroethane

• Ethylbenzene • N-hexane • MTBE

• Xylenes • Methylcyclohexane • Ethanol

• Naphthalene • Methanethiol

• 1,3-butadiene • Ethanethiol

• 1,2,4-trimethylbenzene • Sec-butyl mercaptan

• 1,3,5-trimethylbenzene • Hydrogen sulfide

• VPHv


Chemicals Screening

Criteria Acute not Chronic • Chemical specific to protect human health • Select short term exposure times with durations ranging from 10

minutes to 14 days

Screening Acute not Chronic• Criteria used to screen air monitoring results to determine which

chemicals should be included in Acute RA • If chemical’s maximum concentration is less than the Air Screening

Criteria it will deemed to be of no potential public health concern and will not be included in Acute RA


Screening Criteria Reference Value Organization Type Value Exposure Duration

AEGL - Acute Exposure Guideline Level

NAC/AEGL; COT/AEGL

Emergency Response 10- and 30-min; 1-, 4- and 8-h

ERPG - Emergency Response Planning Guideline

AIHA Emergency Response 1-h

TEEL - Temporary Emergency Exposure Level

DOE Emergency Response 1-h

ERG - Emergency Response Guidebook

DOT Emergency Response Specialized application to determine evacuation zones

MRL - Minimal Risk Level ATSDR Public Health 1-14 days (acute); 15-364 days (intermediate);

>365 days (chronic) REL - Reference Exposure Level

OEHHA Public Health 1-h, 8-h, and chronic

ARfC - Acute Reference Concentration

OECD Public Health Less than 24-h

AMCVs - Acute Monitoring Comparison Values

Texas Public Health 24-h or less

Step 2. Exposure Assessment Provides estimates of from short term exposure: • What is the chemical concentration(s)

measured during the Spill Event that the Public may inhaled

• How long is the Exposure: Daily intake (dose) of chemical(s) by Public

Human intake factors include: • Age • Hours per day exposed; • Breathing Rate

Risk Based Approach - Acute HHRA

Components of Exposure Assessment

Exposure Inhalation

• Consider exposure period • Highest concentrations occur at beginning

of event • Ambient air data considered

representative of 1-hour, 8-hour and 14-day exposure periods following spill event

• Fluctuations can occur due to dispersant usage during spill response

Step 3. Toxicity Assessment Gather information on:

• Acute Adverse Health Effects the chemical(s) may cause

• Concentrations that cause these adverse effects • Short term exposure criteria


Components of Toxicity Assessment

Adverse Effects: • Acute and Subchronic Effects not Chronic

Effects • Need acute and/or subchronic effects

toxicological data, when available, such as: • Decreased lymphocyte count • Developmental toxicity • Motor function • Nasal lesions

Step 4. Risk Characterization Combines results of Step 2 and 3 to :

• Estimate probability and severity of potential risks to Public

Compare the estimated site-specific

doses for each site user to Acute TRVs Calculate risks Uncertainties evaluated Discuss meaning of results


Challenges of Acute HHRA • Dynamic environment during event

• Lack of air monitoring plans specific for public health during spill event

• Acquiring useful data at low detection limits in real time

• Acute criteria selection • Transfer from acute to chronic conditions when

longer term impacts are occurring

Lessons Learned • Monitoring plans need to be proactive not

reactive • Risk assessments need to be tailored to short

term exposure scenarios • Chemicals monitored need to be specific to

product spilled – a long list is not better than short list with actual criteria

• Monitoring instruments need to be sensitive

Components of World Class RA • Comprehensive Air Monitoring Plans that allow

collection of accurate and reliable data • Measurement of chemicals at low detection limits

in real time • Screening level and toxicity reference sources

are respected and recognized organization • RA is proven method to assess human impacts

during and after exposure to chemicals

Thank you!

Questions??